Controller for controlling the properties of light

Abstract

A controller (1) is configured to control the properties of light emitted from a light emitting device (4), the controller comprising a control device (2) and a processing unit (3). The control device (2) enables a user to select a color point of the light emitted from the light emitting device (4) in the color space of the light emitting device. The selection of the color point is performed by the user providing a single input to the control device (2). The processing unit (3) is configured to change the color point of the light emitted from the light emitting device based on the single input. The change of the color point is performed along a meander curve extending along a black body locus (BBL) according to the received single input.

Description

Technical Field

[0001] The invention relates to a controller for controlling properties of light emitted from a light emitting device, wherein the controller comprises a control device and a processing unit. Background Art

[0002] With the advancement of LED technology, lighting systems and lamps with variable color temperature are increasingly used in professional and consumer environments. In such lighting systems, the desired color temperature can be obtained by combining light from several light sources with different colors and / or color temperatures (CT).

[0003] In certain environments, it may be desirable to control not only the color temperature of the output light (i.e., adjusting from a more bluish white light to a more yellowish white light, or vice versa), but also the hue (i.e., a more greenish white light, a more magenta white light, a more cyan white light, or a more reddish white light). However, control systems that provide such control may be complex and difficult for the average user to use.

[0004] US 2018 / 376560 A1 discloses a system that allows a lamp to have a wider range of color temperatures while limiting the hottest temperature reached at full intensity. US 2018 / 376560 A1 also discloses that the intensity can be adjusted from a first handle and the color temperature can be adjusted from a second handle.

[0005] Therefore, there is still a need for a more flexible and easier way to control the color temperature and hue of white light.

[0006] US 2013 / 002157 discloses a light emitting device, comprising: a first LED string, the color point of light emitted by the first LED string is within at least eight MacAdam ellipses of the first blue-shifted-yellow region on the 1931 CIE chromaticity diagram; a second LED string, the color point of light emitted by the second LED string is within at least eight MacAdam ellipses of the second blue-shifted-green region on the 1931 CIE chromaticity diagram; and a third light source, which emits radiation with a dominant wavelength between 600nm and 720nm. A driving circuit provides corresponding driving currents to the first LED string, the second LED string, and the third light source, and at least two of the first LED string, the second LED string, and the third light source are independently controllable. Summary of the invention

[0007] An object of the present invention is to at least partially alleviate the above-mentioned disadvantages of the prior art and further provide a controller, system and method for controlling properties of light which enables a more flexible and easy control way of controlling the color temperature and tint of white light.

[0008] According to a first aspect of the present invention, there is provided a controller, the controller being configured to control properties of light emitted from a light emitting device, the controller comprising:

[0009] Control devices; and

[0010] Processing unit;

[0011] the control device being configured to enable a user to select a color point of light emitted from the lighting device in a color space of the lighting device, the color point being defined based on a hue and a color temperature, wherein selecting the color point is accomplished by a single input provided to the control device,

[0012] The processing unit is configured to change the color point of light emitted from the light emitting device based on a single input received via the control device, wherein the processing unit is configured to change the color point along a meander curve extending along a black body locus (BBL) in dependence on the received single input.

[0013] The controller therefore only needs to receive a single input to change the color point of the light emitted from the lighting device.Thereby, a simple and intuitive way of changing the color point of the light is provided to the user of the controller.

[0014] The processing unit may be configured to change the color point of the light emitted from the light emitting device from a first color temperature to a second color temperature. The first color temperature and the second color temperature are both points on a meander curve.

[0015] Furthermore, by having the processing unit change the color point along a predetermined curve, the user is allowed to easily obtain a desired color point because the change in the color point is easily predictable. Limiting the color point to a meandering curve also reduces the processing power required by the processing unit.

[0016] The meander curve along which the processing unit is configured to change the color point may be given by the manufacturer of the controller, wherein the controller may include a plurality of different meander curves from which the user may select, thereby allowing the user of the controller to achieve a desired color point or a desired change in color point. Thus, the manufacturer may adapt the lighting device to provide light tailored to a specific application requiring specific light properties, thereby providing a customized lighting device.

[0017] The meander curve may alternatively be given by a user defining one or several meander curves, the processing unit being configured to utilize the one or several meander curves to change the color point of the light emitted from the lighting device. Thus, a lighting device is provided that has a great degree of versatility in terms of application, which in turn provides the user with a great degree of freedom in the use of the lighting device.

[0018] In one embodiment of the controller, the meander curve is centered around the BBL.

[0019] By centering the meander curve around the BBL, a wide variety of tones can be obtained.

[0020] In one embodiment of the controller, the meander curve is not centered around the BBL.

[0021] By not having the meander curves concentrated around the BBL, emphasis can be placed on certain hues. This is advantageous, for example in certain settings where it may be preferred to emphasise hues that match the surroundings of the light emitting device.

[0022] In yet another embodiment of the controller, the half period of the meander curve is preferably in the range from 300K to 1000K, in the range from 350K to 700K, or in the range from 400K to 600K, such as 500K.

[0023] Thus, the sensitivity of the controller may be optimized, such as to ensure a high degree of sensitivity relative to the total interval of color temperatures one wishes to cover. A certain degree of sensitivity is required to allow fine tuning of the color point, while too much sensitivity may make the tuning process too cumbersome for the user.

[0024] In one embodiment of the controller, the meander curve intersects the BBL at at least five of the following color temperatures: 6000K, 5500K, 5000K, 4500K, 4000K, 3500K, 3000K, 2700K, 2500K, 2300K.

[0025] Selecting at least some of the above color temperatures as intersections between the meander curve and the BBL ensures that selected color temperatures, here the most commonly used and desired color temperatures in lighting, are represented as controller-achievable choices.

[0026] In one embodiment of the controller, the amplitude of the meander curve is at least 10 standard deviation color match (SDCM), at least 15 SDCM, or at least 20 SDCM.

[0027] By having a minimum in the amplitude of the meander curve, it ensures that when the processing unit is changing the color point of the light emitted from the lighting device, the user notices the change in color temperature as well as the change in hue.

[0028] In one embodiment of the controller, the amplitude of the meander curve decreases with decreasing color temperature.

[0029] Therefore, when selecting a light with a lower color temperature and thus a warmer light, a smaller deviation of the BBL and thus a smaller hue is ensured. This in turn makes the generated light more suitable for the viewer.

[0030] In one embodiment of the controller, the reduction in amplitude is gradual and is at least 10% in one cycle.

[0031] In one embodiment of the controller, the period of the meander curve decreases as the color temperature decreases.

[0032] The controller thus has a greater sensitivity to lower color temperatures and therefore warmer light. This in turn enables the user to further fine tune the color point at lower color temperatures and make the generated light more suitable for the viewer.

[0033] In one embodiment of the controller, the reduction in the period is gradual and is at least 10% of the period.

[0034] In one embodiment of the controller, the meander curve is phase shifted when the color point exceeds or exceeds a preset threshold point of the color point and / or the time derivative of the color temperature changes sign.

[0035] By phase shifting the meander curve, a user of the controller can achieve a wider range of hues, for example if the user has achieved a desired color temperature but wants a different hue, this can be achieved by phase shifting the meander curve.

[0036] In an embodiment of the controller, the processing unit is further configured to reduce the luminous flux of the light emitting device according to the additional curve while reducing the color temperature of the light emitting device.

[0037] Thus, the processing unit may be configured to change the properties of the light emitted from the lighting device not only based on the meander curve adapted to the BBL, but also based on an additional curve. Such an additional curve may indicate the luminous flux of the lighting device according to the color temperature.

[0038] This provides a controller with which further parameters of the possible light output can be adjusted. For example, using an additional curve indicating the luminous flux of the lighting device as a function of the color temperature also provides for including improved dimming effects within the achievable output range.

[0039] In one embodiment of a controller, the control device is a button, dial, slider, or joystick.

[0040] The control device can be a physical object through which the user can provide input to the controller, or it can be a virtual representation such as a button, dial, slider or joystick on a touch screen, through which the user can then communicate a single input to the controller.

[0041] According to a second aspect of the present invention, there is provided a lighting system for controlling the properties of light emitted from a light emitting device, the lighting system comprising:

[0042] A controller according to any of the above embodiments; and

[0043] lamp, lamp or lighting fixture,

[0044] Wherein the controller is communicatively connectable to or is communicatively connected to the lamp, lamp or lighting fixture.

[0045] According to a third aspect of the present invention, there is provided a method for controlling the properties of light emitted from a light emitting device, the method comprising the following steps:

[0046] There is provided a controller according to any embodiment of the first aspect of the invention, and

[0047] providing a single input to a user interface of the controller to control the properties of light emitted from the light emitting device, and

[0048] By means of a processor of the controller, a color point of light emitted from the lighting device in a color space of the lighting device is changed based on a single input received at the user interface.

[0049] Other objects, features and advantages of the present invention will become apparent from the following detailed description, the drawings and the appended claims. Those skilled in the art will realize that different features of the present invention can be combined to create embodiments other than those described in the following. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] This and other aspects of the present disclosure will now be described in more detail, with reference to the appended drawings showing embodiment(s) of the present disclosure.

[0051] Figure 1 A schematic diagram of an embodiment of a controller with a control device and a processing unit is shown, the controller being connected to a lighting device.

[0052] Figure 2 A schematic diagram of a control device in the form of a slider is shown.

[0053] Figure 3 A meander curve fitted to the black body locus (BBL) in color space is shown.

[0054] Figure 4 A zigzag curve centered around the BBL in color space is shown.

[0055] Figure 5 A zigzag curve is shown that is not centered around the BBL in color space.

[0056] Figure 6 A meander curve fitted around the BBL is shown with a half period of 500K.

[0057] Figure 7 A meander curve is shown that fits around the BBL, wherein the amplitude of the meander curve decreases with decreasing color temperature.

[0058] Figure 8 A meander curve fitted around the BBL is shown, wherein the period of the meander curve decreases with decreasing color temperature.

[0059] Fig. 9 A meander curve is shown fitted around the BBL, wherein the meander curve undergoes a phase shift.

[0060] Fig. 10A A meander curve adapted to the BBL in color space is shown.

[0061] Fig. 10B Shown with Fig. 10A The curve shown is associated with an additional curve which controls the light intensity as a function of the color temperature.

[0062] Fig.11 A schematic diagram of a light emitting device in the form of a lamp is shown.

[0063] Fig.12 A schematic diagram of a light emitting device in the form of a lamp is shown.

[0064] Fig.13 A flow chart of a method according to the invention is shown. DETAILED DESCRIPTION

[0065] The present disclosure will now be described more fully hereinafter with reference to the accompanying drawings, in which currently preferred embodiments of the present disclosure are shown. However, the present disclosure may be embodied in many different forms and should not be construed as limited to the embodiments described herein; on the contrary, these embodiments are provided to be thorough and complete and to fully convey the scope of the present disclosure to the skilled person.

[0066] Figure 1 A schematic diagram of an embodiment of a controller 1 according to the present disclosure is shown, the controller 1 being connected to a lighting device 4 .

[0067] Generally, regardless of the embodiment, a controller 1 according to the invention comprises a control device 2 and a processing unit 3 .

[0068] The control device 2 enables a user to select the color point of the light emitting device 4 by giving a single input to the control device 2. The color point is a point in color space that is defined based on hue and color temperature. The color point of the light emitted from the light emitting device 4 can change along a meandering curve that extends along the black body locus (BBL). The color point is a two-dimensional point in color space, where the two dimensions specify the color temperature and the standard deviation of color matching (SDCM).

[0069] The light emitting device 4 may comprise red light emitting diode (LED), green LED(s) and blue LED(s), and the meander curve may be adapted to control the LED(s) individually, thereby allowing control of different color hues. The light emitting device 4 may also comprise warm white LED(s), e.g. 2200K(s) and / or cool white LED(s), e.g. 5000K. The warm white LED(s) and cool white LED(s) may be added primarily for driving color temperature, while the RGB LED(s) may primarily control the hue, thereby reducing the complexity required for the processing unit 3, since each LED primarily requires control of one parameter.

[0070] The black body locus (BBL) (also known as the Planckian locus or white line) is the path or locus that the color of an incandescent black body follows in a particular chromaticity space (e.g., in a chromaticity diagram) as the temperature of the black body changes. The locus changes from deep red to orange, yellow-white, white at relatively low temperatures (about 700K), and finally to bluish-white at higher temperatures.

[0071] So-called MacAdam ellipses are used in color measurement systems to measure how much color variation is possible around the axis of the MacAdam ellipse before the human eye detects a color change. A series of concentric MacAdam ellipses can be drawn around any target color, and the closer any given light output is to the target, the less color deviation there will be when those lamps are placed side by side in an installation. The distance from the target point in each MacAdam ellipse is measured in SDCM (Standard Deviation of Color Match). An SDCM of 1 means there is no visible color difference, 2-3 SDCM means there is barely any visible color difference, and 4 or more SDCM is easily noticeable by the human eye. The lower the number of SDCM, the smaller the color shift.

[0072] The processing unit 3 is configured to change the color point of the light emitted by the light emitting device 4 based on a single input received via the control device 2. When the single input is received, the processing unit 3 will change the color point 5 of the light emitted from the light emitting device 4, and the change of the color point 5 will change along a meander curve in the color space. The meander curve will be further described in detail below. The change of the color point 5 can follow continuously along the meander curve, or it can jump or move suddenly along the curve. The processing unit is configured to increase or decrease the color temperature while causing the SDCM oscillation to achieve different hues at different color temperatures. The meander curve can be any type of curve along a winding route. As a non-limiting example, the meander curve can be a sine curve.

[0073] The processing unit 3 and the light emitting device 4 may be wirelessly connected or connectable, for example, by means of a wireless local area network, WLAN, Bluetooth, Wi-Fi, etc. The processing unit 3 and the light emitting device 4 may also or alternatively be connected or connectable by means of a wired connection, such as a plug and socket connection, a local area network, etc.

[0074] The control means 2 may be represented as buttons, dials, sliders, joysticks etc. Alternatively, the controller 1 may be provided with the control means 2 in the form of a user interface, wherein a virtual representation of the buttons, dials, sliders, joysticks etc. may be provided, and wherein a user of the controller 1 may then interact with the virtual representation of the control means to select a color point via a single input, thereby allowing the processing unit 3 to change the properties of the light emitted from the light emitting means 4 connected or connectable to the processing unit 3 based on the single input. Such a user interface may for example be a touch screen, such as the touch screen of a mobile phone, tablet computer, laptop computer etc.

[0075] Reference now Figure 2 and Figure 3 , Figure 2 An embodiment of a control device 2 according to the invention is shown, and Figure 3 A meander curve 6 in a color space according to the present invention is shown. The control device 2 shown is in the form of a slider 21. The slider 21 allows a user to pass a single input to the control device 21 by moving the slider 21. The meander curve 6 in the shown embodiment is adapted along the BBL. Different adaptations can be performed, and some of them will be described later. The control device 21 can have a meander curve 6 directly associated with it, which can be performed by making the ends of the slider 21 correspond to two different curve values ​​on the meander curve 6, wherein the first slider end 211 corresponds to a first curve value 61 with a high color temperature and the second slider end 212 corresponds to a second curve value 62 with a low color temperature. The slider step between the two ends then corresponds to a color temperature value between the first curve value 61 and the second curve value 62. Similar implementations can be implemented using different types of control devices 2, such as joysticks, dials, etc.

[0076] Such a setting allows an easy overview of the available settings and intuitive control of the properties of the light. As described above, in the case where the control device is of the type where the control device itself does not define a range, such as being provided with two ends of a slider, the meander curve may be predetermined with a high threshold and a low threshold of color temperature, for example, the first curve value 61 and the second curve value 62 being the high threshold and the low threshold, respectively. The processing unit 3 may then be configured such that a push of the control device 2 (e.g. as a button) signals the processing unit 3 to change the color point towards the first curve value 61. When the first curve value 61 is subsequently reached, the processing unit 3 may be configured to change the color point towards the second curve value 62, thereby allowing the user to reach all color temperatures between the first curve value 61 and the second curve value 62, for example in the case where the processing unit 3 increases the color temperature when the control device 2 is pressed, and when the first curve value 61 is reached, it may be configured to start decreasing the color temperature when the control device 2 is pressed again.

[0077] Reference now Figure 4 and Figure 5 , showing two different possibilities for the predetermined curve, both of which are meandering curves adapted to the BBL. Figure 4 In the embodiment, the meander curve 7 is fitted centrally around the BBL, so that the average value of one period of the meander curve 7 is zero. By fitting the meander curve 7 centrally around the BBL, a large number of tones are available to the user. Figure 5 The meander curve 8 shown is arranged non-centrally around the BBL, ie the average value of one period of the meander curve 8 is not zero. This may be advantageous if a particular hue needs to be emphasized.

[0078] refer to Figure 6 , shows another possibility of a meander curve 9 adapted to the BBL. The half period of the meander curve 9 shown is 500K. The half period of the meander curve adapted to the BBL may be in the range of 300K to 1000K, or in the range of 350K to 700K or in the range of 400K to 600K. The meander curve 9 shows the intersection with the BBL at 6000K, 5500K, 5000K, 4500K, 4000K, 3500K, 3000K or 2500K, but different curve adaptations may intersect the BBL at different points, and the intersection may also occur at 2700K and 2300K. The amplitude of the meander curve adapted to the BBL may be at least 10SDCM, 15DCM or 20SDCM.

[0079] refer to Figure 7 and Figure 8 , shows two other meander curves adapted to the BBL. Figure 7 The meander curve 10 seen in FIG. 1 is adapted to have an amplitude that gradually decreases as the color temperature decreases. Alternatively, the amplitude may gradually increase as the color temperature decreases. The amplitude change may also be performed in steps rather than gradually. When changing from a warmer color to a cooler color or vice versa, the reduction in amplitude may be configured to be at least 10% over one cycle of the meander curve 10. Figure 8 The meander curve 11 seen in FIG. 1 is adapted to gradually reduce the period of the meander curve 11 as the color temperature decreases. Alternatively, the period may gradually increase as the color temperature decreases. The period change may also be performed stepwise rather than gradually. When changing from warmer colors to cooler colors, the reduction in period may be configured to be at least 10% over one period of the meander curve 11.

[0080] Fig. 9 Another adaptation of the meandering curves 12a, 12b along the BBL according to the present disclosure is shown. Fig. 9As shown, the processing unit 3 may be adapted to phase shift the adapted curve. The processing unit 3 may be provided with a threshold point in the color space, wherein the processing unit 3 is adapted to phase shift the meander curve when the threshold point is reached, or it may be done as a response to the time derivative of the sign of the color temperature change. The processing unit 3 may be configured to phase shift the meander curve by π, 0.5π, 0.25π, etc. By phase shifting the meander curve, the user may be allowed to select a wider range of hues. The threshold for phase shifting the predetermined curve may also indicate that the processing unit 3 should start to reduce the color temperature rather than increase the color temperature, or vice versa, upon receipt of a single input, thereby allowing the user to use a wider range of hues. In the case where a range has been displayed on the control device, for example as seen with a slider having two ends thereof, the processing unit 3 may be configured to phase shift the meander curve whenever an end value of the range is reached, for example when the slider is moved to either end of the slider. As Fig. 9 As shown by the two meander curves 12a and 12b on FIG. 1 , the processing unit 3 may be configured to phase shift the meander curves whenever the meander curves change from decreasing color temperature to increasing color temperature or vice versa.

[0081] Fig. 10A and Fig. 10B A meander curve adapted to the BBL and the associated luminous flux curve are shown.In addition to the meander curve associated with it, the processing unit 3 may also be provided with additional curves. Fig. 10B An example of such an additional curve 14 is shown. The additional curve 14 may control additional properties of the light emitted from the light emitting device 4, which additional properties may be related to the color point of the light or may be related to other properties of the emitted light. Fig. 10B The additional curve 14 shown determines the luminous flux of the lighting device 4 according to the color temperature, wherein the luminous flux decreases as the color temperature decreases. The additional curve 14 can also be set to increase the luminous flux of the lighting device 4 when the color temperature decreases.

[0082] Reference now Fig.11 and Fig.12 , showing different lighting devices 4, to which a controller 1 according to the present disclosure may be communicatively connected or may be communicatively connected. Fig.11 A lamp 41 is shown, and Fig.12 4 is shown as an example of the light emitting device 4 having a light exit surface that emits emitted light, but the present disclosure is not limited thereto and may be performed using various different lamps.

[0083] The described disclosure also encompasses methods for controlling properties of light emitted from a light emitting device, Fig.13A flow chart illustrating an embodiment of such a method is shown. The method comprises three steps, a first step 100 providing a controller according to the present disclosure, a second step 200 providing a single input to a user interface of the controller to control the properties of the light emitted from the lighting device, and a third step 300 changing the color point of the light emitted from the lighting device based on the single input received at the user interface.

[0084] A specific embodiment of the invention has now been described. However, as will be apparent to a person skilled in the art, several alternatives are possible. For example, the processing unit 3 may be configured to adapt the color point of the light emitted from the light emitting device 4 by combining the different adaptations presented, for example, the curve may be non-central and also undergo a phase shift, so that different combinations of the presented meander curves must be considered within the scope of the invention as defined in the appended claims.

Claims

1. A controller (1) configured to control properties of light emitted from a light emitting device (4), the controller comprising: Control device (2); as well as Processing unit (3); The control device (2) is configured to enable a user to select a color point of the light emitted from the lighting device in a color space of the lighting device, the color point being defined based on hue and color temperature, wherein the selection of the color point is accomplished by a single input provided to the control device, The processing unit (3) is configured to change the color point along a meandering curve, thereby allowing the user to adjust the color point of the light emitted from the light emitting device based on the single input received via the control device, wherein the processing unit is configured to change the color point along the meandering curve extending along the black body locus BBL according to the single input received, Wherein the half period of the meander curve is in the range from 300K to 1000K, in the range from 350K to 700K, or in the range from 400K to 600K, such as 500K, and wherein the amplitude of the meander curve is at least 10 standard deviation color matching SDCM, at least 15SDCM or at least 20SDCM. 2 . The controller of claim 1 , wherein the meander curve is centered around the BBL. 3 . The controller according to claim 1 , wherein the meandering curves are not concentrated around the BBL.

4. The controller of claim 1 or 2, wherein the meander curve intersects the BBL at at least five of the following color temperatures: 6000K, 5500K, 5000K, 4500K, 4000K, 3500K, 3000K, 2700K, 2500K, 2300K.

5. The controller according to claim 1 or 2, wherein the amplitude of the meander curve decreases as the color temperature decreases.

6. A controller according to claim 5, wherein the reduction in amplitude is gradual and is at least 10% in one cycle.

7. The controller according to any one of claims 1, 2 or 6, wherein the period of the meander curve decreases as the color temperature decreases.

8. A controller according to claim 7, wherein the reduction in the cycle is gradual and is at least 10% in one cycle.

9. A controller according to any one of claims 1, 2, 6 or 8, wherein the meander curve is phase shifted when the color point exceeds or reaches a preset threshold point of the color point and / or the time derivative of the color temperature changes sign.

10. The controller according to any one of claims 1, 2, 6 or 8, wherein the processing unit is configured to reduce the luminous flux of the light emitting device according to an additional curve (14) while reducing the color temperature of the light emitting device.

11. The controller according to claim 1, wherein the control device (2) is a button, a dial, a slider or a joystick.

12. A lighting system for controlling a property of light emitted from a light emitting device, the lighting system comprising: A controller (1) according to any one of the preceding claims; as well as a lamp (41), a lamp (42) or a lighting device, The controller is communicatively connectable to the lamp, the lamp fixture or the lighting fixture, or the controller is communicatively connected to the lamp, the lamp fixture or the lighting fixture.

13. A method of controlling the properties of light emitted from a light emitting device (4), the method comprising the steps of: There is provided (100) a controller (1) according to any one of claims 1 to 12, and providing (200) a single input to a user interface of the controller to control the property of light emitted from the light emitting device, and By means of the processing unit (2) of the controller, the color point of the light emitted by the lighting device in the color space of the light emitted by the lighting device is changed (300) based on the single input received at the user interface.

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